Answer: Your "Candida" clematis belongs to what is called the Lanuginosa Group of clematis vines, the group being identified as having C. lanuginosa as a parent. Most of these vines will bloom in June on wood from the previous year and again later in the season on the new growth for the current year. If you prune it back to about three feet in the spring, you would see a better flower display but later in the season. According to Michael Dirr's "Manual of Woody Landscape Plants" some of the vines in this group may produce double flowers on the old wood and single flowers on the new growth of the season. Other than pruning, the care would be the same as for your Jackman.
Q&A Library Searching Tips